Hmmm ... This is the second time in the past year that I am apparently not seeing what other people are seeing! I'm using Firefox 54.0.1 on Win7x64. I normally use the Drag and Drop editor as my default. I just tried Internet Explorer and saw the same results.
On my iPad, in Safari, the editor defaults to the old style edit and clicking the link to switch to Drop and Drag has no effect.
So I fear we have exhausted my knowledge on the topic! To the good side, a news flash line is saying we now get 2GB storage for $23 a year.
The other thing I notice, which I think I would have noticed long before this if it was there. In Drag and Drop, when 'Content' is showing all the thumbnails, if I move the cursor over a thumbnail, under the "Selection: " line in the panel at the top, a second line appears with "Image: ", the title of the image, the size in pixels and in bytes, and the number of hits. Never noticed that before, so that might actually mean there is still somebody alive at headquarters and they are actually working on something.
I'm sorry I don't seem to be able to offer any real help. I can only recommend logging out of PBase, and as
richo suggests, clearing the browser cache AND any cookies related to PBase, then logging in again.
Oh, one other thing I've noticed with the drag & drop editor, if one clicks on other galleries in the tree displayed in the left hand panel, the edit panel sometimes doesn't appear to keep track of where it is operating.